Under the agreement, Eisai will grant Roivant an exclusive worldwide license (including Japan) concerning the research, development, manufacture and marketing of E6005. Currently, E6005 is at the Phase II clinical trial stage for atopic dermatitis in Japan, and Roivant will conduct research and development going forward. Furthermore, according to the agreement, Eisai will receive a one-time upfront payment from Roivant, and will also receive milestone payments in line with future development progress as well as specified royalty payments after market launch.

Discovered in-house by Eisai’s Tsukuba Research Institute, E6005 is a selective PDE4 inhibitor. It is known that PDE4 is an enzyme that degrades the second messenger cyclic AMP. PDE4 is involved in inflammation and the immune response. In non-clinical and clinical studies conducted to date by Eisai, E6005 exhibits anti-inflammatory effects and suggests suppression of itching relating to atopic dermatitis by selectively inhibiting PDE4. Furthermore, in clinical studies of the agent in adult and pediatric patients with atopic dermatitis, no serious safety concerns that could pose problems in a clinical setting were observed. As it is known that the interaction between itching and inflammation leads to worsening and the chronic state of atopic dermatitis, E6005 has the potential to become a new treatment option for atopic dermatitis with its demonstrated effect on reducing inflammation and suppressing itching as well as favorable safety profile.

Roivant is a pharmaceutical company with a unique business model of strategically acquiring businesses and pipeline products from other companies. Eisai positions oncology and neurology as its key therapeutic areas, and focuses investment of research and development resources accordingly. By licensing E6005, which will be known as RVT-501 going forward to Roivant, Eisai aims to maximize the value of the compound as well as accelerate its development in order to contribute to the treatment of patients with inflammatory/autoimmune diseases starting with atopic dermatitis as soon as possible.

About E6005 (Roivant development code: RVT-501)

E6005 (RVT-501) is a selective phosphodiesterase 4 inhibitor discovered in-house by Eisai. Distributed in many cells involved in inflammation and immune response, PDE4 is an enzyme that influences the transmission of inflammation signals by degrading the intracellular signaling molecule cyclic AMP. It is reported that exacerbation of PDE4 activity leads to increased production of inflammatory mediators, making the condition worse and chronic in nature, and at atopic dermatitis lesion sites, exacerbation of PDE4 activity can be observed. In non-clinical and clinical studies conducted by Eisai, E6005 exhibits anti-inflammatory effects and suggests suppression of itching relating to atopic dermatitis by selectively inhibiting PDE4. Currently, E6005 is at the Phase II stage of clinical trials as a transdermal PDE4 inhibitor for adults and pediatric patients with atopic dermatitis, and with its demonstrated effect on both reducing inflammation and suppressing itching as well as favorable safety profile, E6005 has the potential to become a new treatment option for atopic dermatitis.